I didn't display bookmarks when default and not ui.quiet: it seems
strange for templates to depend on --id or -q, and it would take more
code for hg id url -T {node} to not request remote bookmarks.
An alternative I thought of was providing lazy data to the formatter,
fm.data(bookmarks=lambda: fm.formatlist(getbms(), name='bookmark')).
The plainformatter would naturally not compute it, the
templateformatter would compute only what it needs, and the other ones
would compute everything, but that's not supported (or I don't see
how), so I abandoned this idea.